Antibacterial keyboard

ABSTRACT

The present invention relates to an antibacterial key for use in a keyboard of a musical instrument. The antibacterial key comprises a key stick and a key cover adhered on the upper surface of the key stick through an adhesive layer. The adhesive layer comprises an adhesive containing a volatile antibacterial agent and can readily add an antibacterial function to the key with an antibacterial effect of the antibacterial agent, which volatilizes from the adhesive layer, at a low cost irrespective of a material or a manufacturing method of the key cover.

FIELD OF THE INVENTION

The present invention relates to antibacterial keys for musicalinstruments having a keyboard to which antibacterial treatment isperformed for preventing the proliferation of bacteria thereon.

BACKGROUND OF THE INVENTION

An antibacterial bacterial key is disclosed in Japanese PatentApplication NO. 7-107373. An antibacterial function is added to akeyboard because a musical instrument having a keyboard is often usedcommonly by a large number of persons, particularly, in school, so thatthere is a fear that bacteria attached on fingers of a person betransferred to fingers of another person who next plays the musicalinstrument through the keyboard. An antibacterial key comprises a keystick and a key cover adhered to the upper surface of the key stick. Thekey cover is made of synthetic resin containing an antibacterial agent.Specifically, calcium phosphate including metal silver is used as theantibacterial agent. A predetermined amount of the antibacterial agentis added to a palette of acrylic resin, uniformly distributed therein,and molded by injection molding. According to this structure, theantibacterial effect of the antibacterial agent included in the keycover prevents bacteria from proliferating on the key, thus maintainingthe cleanliness on the key as well as preventing discoloration of thekey.

However, with the conventional antibacterial key, since the key cover isformed by injection molding acrylic resin containing an antibacterialagent, the antibacterial agent acts as an impurity during the injectionmolding, thus disadvantageously causing difficulties in producing auniform key cover, for example, moire patterns may appear on the surfaceof a molded key cover. Therefore, the yield of the molds is reduced, andthis causes the cost to increase.

It is therefore an object of the present invention to provide anantibacterial key which is capable of readily adding an antibacterialfunction at a low cost irrespective of a material or a manufacturingmethod of a key cover.

SUMMARY OF THE INVENTION

According to the present invention, there is provided an antibacterialkey which comprises a key stick and a key cover adhered to the uppersurface of the key stick with an adhesive layer, wherein the adhesivelayer includes an adhesive containing a volatile antibacterial agent.

According to this antibacterial key, the adhesive layer exposes on theside surfaces of the key between the key stick and the key cover, sothat the antibacterial agent included in the adhesive layer alwaysvolatilizes from the side surfaces to the outside to surround the key.Thus, the action of the antibacterial agent prevents bacteria fromproliferating on the key, resulting in maintaining the cleanliness ofthe key as well as preventing discoloration due to the proliferation ofbacteria.

In this way, the antibacterial key of the present invention provides anantibacterial effect by the antibacterial agent volatilizing from theadhesive, so that an antibacterial function can be added irrespective ofa material or a manufacturing method of the key cover. Particularly,when a key cover is molded by injection molding acrylic resin, theaddition of an antibacterial agent to the acrylic resin is not required,so that defective molds due to the addition are eliminated, resulting inan increased yield and hence a reduced cost. Also, the antibacterialfunction can be readily added to any key only by adding theantibacterial agent to an adhesive generally used in the manufacture ofkeys.

Preferably, the key cover is made of a porous material. An artificialivory often used generally in key covers falls under this porousmaterial. With this construction, the antibacterial agent included inthe adhesive layer volatilizes not only from the side surfaces of thekey but also from the upper surface of the key cover after theantibacterial agent passes through the pores and permeates the keycover, thus making it possible to more effectively perform theantibacterial function.

Also preferably, the antibacterial agent comprises calcium phosphatecontaining one or more metals selected from a group including silver,copper, and zinc. According to this construction, the antibacterialactivity possessed by these metals provides an effective antibacterialeffect. In this case, metal silver is particularly preferable since ithas been used as table services, coronas, and so on and exhibits highsafety to human bodies. In addition, when calcium phosphate is used as acarrier for carrying a metal, the safety can be ensured.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a key (white key) of an acoustic pianoto which the present invention is applied;

FIG. 2 is a perspective view of a key cover for the key of FIG. 1;

FIG. 3 is a cross-sectional view taken along a line III—III in FIG. 1;and

FIG. 4 is a cross-sectional view, similar to FIG. 3, of a key accordingto a second embodiment of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

A preferred embodiment of the present invention will hereinafter bedescribed in detail with reference to the drawings. FIG. 1 illustrates akey (white key) of an acoustic piano to which the present invention isapplied. The key 1 comprises a key stick 2 and a key cover 3. The keystick 2 is made of a solid woody material such as spruce and hassubstantially a uniform rectangular cross-section. The key cover 3 ismade of acrylic resin such as methyl methacrylate resin, similar to anormal key cover, and is injection molded into a shape as illustrated inFIG. 2 by an injection molding machine, not shown. Then, the key cover 3is adhered to a front portion of the upper surface and the front surfaceof the key stick 2 by an adhesive layer 4, as illustrated in FIG. 1, tocomplete a playing area which is directly touched by a finger of aplayer for playing the piano.

The adhesive layer 4 is composed of an adhesive comprising, for example,aqueous vinyl urethane, and a predetermined amount of an antibacterialagent uniformly distributed in the adhesive. As the antibacterial agent,“Apacider A” (a registered trademark) (manufactured by Sangi Co.), forexample, may be used. The Apacider A employs calcium phosphate(hydroxyapatite or tri-basic calcium phosphate) as a carrier whichcarries metallic silver, and is manufactured as a ceramic material,wherein a mixture of calcium phosphate and silver compound is sinteredat high temperatures equal to or higher than 1000° C., and during thissintering process, silver ions in the silver compound are alltransformed into metallic silver. The complete transformation of thesilver ions into metallic silver has been confirmed from the fact thatno silver ions are eluted in water by conducting an analysis accordingto the atomic-absorption spectroscopy (the analysis limit is 0.05 ppm).

With the key 1 constructed as described above, the adhesive layer 4 isexposed on the side surfaces between the key stick 2 and the key cover3, as illustrated in FIG. 3, so that the antibacterial agent included inthe adhesive layer 4 gradually volatilizes from the side surfaces to theoutside and surrounds the key 1. As a result, the proliferation ofbacteria on the key 1 is prevented by the action of the antibacterialagent, thereby making it possible to maintain the cleanliness of the key1 as well as to prevent discoloration of the key due to theproliferation of bacteria. In addition, since the apacider A, i.e., aceramic material made by sintering a mixture of metal silver and calciumphosphate is employed as the antibacterial agent, the components havehigh safety to human bodies and environment. Also, the ceramic materialexhibits an excellent stability and therefore provides the antibacterialeffect for a long term.

In this way, the key 1 of this embodiment can be readily provided withthe additional antibacterial function only by adding the antibacterialagent to an adhesive which is generally used for the manufacture. Forthis reason, the key cover 3 itself need not have the antibacterialnature so that it can be manufactured by a injection molding techniquesimilar to generally used ones, thus resulting in an increased yield andconsequently a reduced cost.

FIG. 4 illustrates a key 11 according to a second embodiment of thepresent invention. The key 11 differs from the foregoing firstembodiment only in that a key cover 13 is made of porous artificialivory. The key cover 13 may be manufactured, for example, in thefollowing way.

Cellulose acetate flake is applied with:

27 wt % of phthalate plasticizer;

0.2 wt % of epoxy compound and 0.3 weight percent of alkyl phosphate asa thermal stabilizer;

30 wt % of silica with a silanol base of 2.1 per 100 square angstrom, aBET ratio surface area of 136 m²/g, and an average grain diameter of 0.9μm as silica; and

2.5 wt % of white pigment, stirred for four hours at 80° C. using auniversal stirrer for mixing them, and simultaneously dried until awater content is reduced to 0.2 wt % or less.

Next, the mixture is melted and kneaded at 220° C., and extruded usingan extruder having a diameter of 40 mm so that the mixture istransformed into pellets.

Finally, the key cover 13 is molded by an injection molding machineusing the pellets.

The key cover 13 molded in the foregoing way includes a large number ofpores internally formed as illustrated in FIG. 4. Thus , the key 11 ofthis embodiment can more effectively perform an antibacterial functionsince the antibacterial agent included in the adhesive layer 4volatilizes not only from the side surfaces of the key 11 but also fromthe upper surface of the key cover 13 after the antibacterial agentpermeates the key cover 13 through the large number of pores 14. Inaddition, since the key cover is made of cellulose derivative resincontaining particular silica, the key 11 advantageously provides abetter hygroscopic property, a comfortable touch feeling with a finger,a firm structure, a good workability, and so on.

The present invention can be implemented in a variety of forms withoutlimited to the embodiments described above. For example, while thedescribed embodiments have shown examples in which the present inventionis applied to a white key of an acoustic piano, the present inventioncan of course be applied to black keys as well as to other musicalinstruments having a keyboard such as organs, electronic pianos, and soon. Also, the kind of antibacterial agent is not limited to theillustrated Apacider A, i.e., a ceramic material formed of a mixture ofsintered metal silver and calcium phosphorate, but may be any agentincluding another metal having the antibacterial activity such ascopper, zinc, or the like, or including any other material than calciumphosphorate as a carrier. Further, it is not essential that theantibacterial agent has the form of a ceramic material. In addition,details in construction can be modified as required without departingfrom the gist of the present invention.

What is claimed is:
 1. An antibacterial key having sides and a top, saidkey comprising: a key stick; and a key cover adhered to only an uppersurface of said key stick by an adhesive layer, said adhesive layerhaving a volatilizing antibacterial agent therein, wherein saidantibacterial agent volatilizes from side surfaces of said adhesivelayer and surrounds the sides and top of the key to provide anantibacterial effect.
 2. The key of claim 1, wherein the key cover ismade of a porous material and said antibacterial agent further passesthrough the porous material of the key cover and volatilizes from anupper surface of the key cover.
 3. The key of claim 1, wherein theantibacterial agent comprises calcium phosphate and at least one metalselected from the group consisting of silver, copper and zinc.
 4. Thekey of claim 2, wherein the antibacterial agent comprises calciumphosphate and at least one metal selected from the group consisting ofsilver, copper and zinc.
 5. The key of claim 3, wherein the at least onemetal is silver.
 6. The key of claim 4, wherein the at least one metalis silver.
 7. A key cover having a top and a bottom adapted to bepositioned on a key stick, only said bottom of the key cover beingadhered to said key stick by an adhesive having a volatilizingantibacterial agent therein to form a key having sides and a top,wherein said antibacterial agent volatilizes from side surfaces of saidadhesive layer and surrounds the sides and top of the key to provide anantibacterial effect.
 8. The key cover of claim 7, wherein the key coveris made of a porous material and said antibacterial agent further passesthrough the porous material of the key cover and volatilizes from anupper surface of the key cover.
 9. The key cover of claim 7, wherein theantibacterial agent comprises calcium phosphate and at least one metalselected from the group consisting of silver, copper and zinc.
 10. Thekey cover of claim 8, wherein the antibacterial agent comprises calciumphosphate and at least one metal selected from the group consisting ofsilver, copper and zinc.
 11. The key cover of claim 9, wherein the atleast one metal is silver.
 12. The key cover of claim 10, wherein the atleast one metal is silver.
 13. A method of providing an antibacterialeffect to sides and a top of a key which comprises a key cover and keystick, comprising: incorporating a volatile antibacterial agent into anadhesive layer; and adhering the key cover to the key stick with theadhesive layer, wherein the adhesive laver is applied only between anupper surface of the key stick and a bottom surface of the key stick,whereby the antibacterial agent volatilizes from side surfaces of saidadhesive layer, thereby providing said sides and top of the key with anantibacterial effect.
 14. The method of claim 13, wherein the key coveris made of a porous material and said antibacterial agent further passesthrough the porous material of the key cover and volatilizes from anupper surface of the key cover.
 15. The method of claim 13, wherein theantibacterial agent comprises calcium phosphate and at least one metalselected from the group consisting of silver, copper and zinc.
 16. Themethod of claim 14, wherein the antibacterial agent comprises calciumphosphate and at least one metal selected from the group consisting ofsilver, copper and zinc.
 17. The method of claim 15, wherein the atleast one metal is silver.
 18. The method of claim 16, wherein the atleast one metal is silver.